Starving black hole quickly sends shining galaxy into shadow

Markarian 1080's wild swings from dim to bright and back again may be due to a second supermassive black hole in its centre.

This image shows the active galaxy Markarian 1018 which has a supermassive black hole at its core. The faint loops of light around the galaxy are a result of its interaction and merger with another galaxy in the recent past.

ESO / CARS survey

A chance observation has uncovered a galaxy flaring brightly before dialling it down again – all in just a few years – because the supermassive black hole in its centre ran out of fuel.

In two papers to be published inAstronomy & Astrophysics, researchers from Europe, the US and Australia tracked the brightening and dimming of the galaxy Markarian 1018 with ground and space telescopes and deduced that its supermassive black hole, which had been feeding voraciously, has fallen on hard times.

“We were stunned to see such a rare and dramatic change in Markarian 1018," says Rebecca McElroy from the University of Sydney in Australia and the ARC Centre of Excellence for All Sky Astrophysics, and lead author of the discovery paper.

They report in a second paper that the galaxy's supermassive black hole was slowly fading because it was being starved of material.

An intriguing possibility, McElroy says, is that there might be two supermassive black holes there.

"Such a black hole binary system is a distinct possibility in Markarian 1018, as the galaxy is the product of a major merger of two galaxies – each of which likely contained a supermassive black hole in its centre."